900hpSS

could anyone clear this up for me? i want to know what the difference is between a cam with an lsa + advance is and just a regular grind. for example what is the difference between a 112+2 and a 114 LSA? i have read the lower lsa will give you a chopy idle. so witch one of these will give you the chopiest idle? or is it the same? any other differences?

bczee

iTrader: (12)

If you read the sticky in the Gen III internal - Cam Guide... section D, it will explain it.

https://ls1tech.com/forums/generation-iii-internal-engine/327734-cam-guide.html

As you stated.. in general, a Low LSA will be a chopy idle.. but LSA, Duration and Lift also comes into play to give a smooth or rough idle.

900hpSS

thanks i did already read that but it doesn't say if a cam on a 112+2 will act the same as a 114 cam. that is what i really need to know. if they do act the same how do you pick the appropriate LSA. thanks

mxmatt137

Typically a smaller lobe seperation will increase lope at idle. However, the smaller LSA will also produce torque earlier/stronger. The wide lsa's are great for a sleeper or stock cams.

The 112+2 means it has 2 degrees advance ground in. Advancing a cam lowers the RPM band that the cam makes power. Basically, if you advance a cam you will make better low/midrange power, whereas, if you retard the cam you get more peak power.

Hope this answers your questions.

900hpSS

thanks for the info. i think i was thinking about the whole thing wrong. i was thinking grinding in some degrees of advance was the same as changing the whole LSA. thanks guys

900hpSS

ok another question. if i have a 112 cam will advancing it change the chopy idle. also what are the advantages of have the advance ground in as opposed to just installing the cam with advance.

and i think i was thinking of the whole thing backwards a 112+2 will act more like a 110 than a 114 right.

thanks again guys. just trying to understand the theory behind all of this.

s346k

iTrader: (4)

basically, a cam on a 112 lsa will act nothing like a 110 or 114 either one, almost regardless of how much advance / retard is ground into it. the LSA itself is 90% of the cam's attitude (in terms of LSA+*), the +2 or whatever is like the remaining 10%. determine what you want and go from there. there is a ****-ton more to LSA than idle behavior - get to reading.

my saying: street cars have advance ground cams.

V8Rumble

iTrader: (9)

Maybe I can play "devil's advocate" for a moment..

Discussions like these are valuable not just to the original poster, but also to others who may have the same question. And reading is all well & good, but limiting yourself to just that deprives you of the chance to hear from others' experience, particularly experience with the same vehicle as you're working on.

So yes, I'd definitely recommend that someone read as much as they're able to on the subject, but (IMHO) it would be foolish to close discussion on this thread.

Just my 2c...

s346k

iTrader: (4)

i would agree with this statement if there already weren't 437894789729 threads pertaining to this EXACT subject. stop taxing others for work you can do yourself...what's the harm in that request?

V8Rumble

iTrader: (9)

Looking on just the first page of this forum, I see six threads that mention camshafts (and one of those was an apparent double-post). I could very well be missing something, but I don't recall seeing ANY threads that mention the specific "behavioral" changes (for lack of a better term) that come with different advances ground in.

I definitely agree that searching & reading should be the first course of action when someone has a question like this. And your point is valid for most of the cam threads I've seen here, which is why I feel that bczee's response was nearly "right on target". But the specific info that the OP was looking for wasn't outlined in much detail there, so I felt that it wasn't out of place if someone else wanted to expand on it a bit.

Basically, I think that we're largely in agreement, maybe just looking at it a bit differently...

wolfy

iTrader: (1)

1. what he said. a 112 + 2 cam is not gonna act like a 110 or a 114 cam. it still has an LSA of 112, the lobes are just ground 2* earlier in the cycle. think of it like this; the LSA is how many degrees apart the intake and exhaust lobes are, the advance (+ 2* in this case is moving both intake AND exhaust lobes 2* forward in the cycle. so now both intake and exhaust begin to open 2* early and close 2* later, but they are still 112* apart...hope that makes sense.

2. what he said again...start reading and learning. a great place to start is here: Comp Cams tech page